Disazo dye



Flo Drawing.

WALTER M. RALPH, 0F BUFFALO, FIEW YORK, A$SIGNOR T0 NATIONAL ilL'N'ILINE & CEEMIUAL CO., INC, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

DISAZO DYE.

T 0 all whom it may concern Be it known that I, WALTER M. RALPH, a citizen of the United States, residing at Buffalo, in the county'of Erie, State of New York, have invented certain new and useful Improvements in Disazo Dyes; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the artto which it appertains to make and use the same.

The present invention relates to a new disazo dye which is of value for dyeing cotton, wool, silk, and other fibers, and which can be developed on the fiber. The inventionincludes the dyed fabrics or other materials, dyed with the new dyestufl, as well as the new dyestuff itself.

The new dyestufi can be obtained by :1} diazotizing nitro Cleves acid, coupling the 'diazo compound so obtained with mi-aminop-cresol methyl ether, diazotizing the m0- nazo compound .thus produced and coupling the same in alkaline solution with gamma acid (2.8.6 aminonaphthol sulfonic acid), and finally reducing the nitro group, e. 9., with sodium disulfid.

The following specific example will further illustrate the invention, the parts being by weight:

29 parts of the sodium salt of l-aminoinitro-naphthalene-6 (or -7) monosulionic acid, or a mixture thereof, hereinafter referred to as nitro Cleves acid, in aqueous solution, are treated with 6.9 parts of sodium nitrite and the mixture is ,run gradually into a mixture of ice and water contaihing 29 parts of hydrochloric acid (20 1%.). By proceeding in this manner, a smooth and rapid diazotization of the nitro Cleves acid is effected. To the result usual way for an excess of either the diazo compound or the m-amino-p cresol methyl ether with alkaline R-salt solution or diazotized p-nitranilin solution. When the coupling is complete the monoazo dye, which has separated as a brownish red product, is filtered of.

Specification of Letters Patent.

Patented Mar. 15, 19211.

Application filed April as, 1920. Serial No. 376,277.

The monoazo dye is then stirred up with I 500 parts of water and dissolved b the addition of sodium hydroxid su cient to effect solution. To this solution is then added 6.9 parts sodium nitrite and diazotization is elfected by running the mixture into ice water containing 29 parts of hydrochloric acid (20B.). place immediately with a partial separation of the diazo compound. The solution or suspension of the diazo compound thus produced is then added gradually to a cold solution of 23.9 parts of gamma acid (2.8.6- amino naphthol sulfonic acid) in water containing enough soda ash to dissolve the and an alkaline solution is maintained up 7 to the end of the addition. After all the diazo compound hasbeen added, stirring is continued for about 1 hour to allow completion of the coupling, after which the solution is heated to about C. and the 80 dyestuff separated in the form of its sodium salt by the addition of common salt (sodium chlorid). The dye is then filtered oil.

The filtererLdye thus obtained is then admixed with about 1000 parts of hot water and reduced at a temperature of about 70 C. by the gradual addition of a solution of sodium disulfid. The reduction is easily followed since the unreduced dye isof a purplish color which turns reddish on the addition of acid, whereas the reduced product is a greenish blue which turns a brightblue with acids. Addition of sodium disulfid is continued until no further development of the blue color is observed. Salt is then added to precipitate the dye in the form of its sodium salt, and the dye is then filtered, dried and ground.

In the dry and pulverized condition, the

dye, in the form of its sodium salt, is a bluish black powder which dissolves in water with a blue color.. Hydrochloric acid produces a blue precipitate from such solution. Sodium hydroxid produces little change. sulfuric acid with a greenish blue coloryand the resulting solution on dilution with water yields a violet precipitate.

The new dye can be used to dye cotton,

wool, silk, and other fibers, giving blue 1 Diazotization takes The dye dissolves in concentrated shades which may be ,developod to give fast blue-black or greemblaok Shades by dimotizing and developing on the fiber or fabric with botzznaphizhoi, m-phenylenodizmnin m-toiylonedizunim yesoroin, etc. 7

The dyed 1m produced eitherby tho mm of the new dyostdfi ifisoli", or by do voloping the new dy-skufif on the fiber or fabric, We ll as the new dyostu'fl' itself, form a pant of the present invention.

I claim:

1. The herein described new disazo dye obtainable by dim-nothing; lmmino-d-nitronaphthalene-G (or -7 )1 moimsulfonio acid COHlldiIlQf with mrumino-p-creso1 methyl other, again diamo 1;; 2nd ootqlding in: dimcotized amm die with $33.6 aminoim'ohthol suifonio 21c) soiddyo, in the form 01 its aodium b01215; iiiuish black pow der, soluble in later to give zpbluo solution "from which hydrochloric acid produoos a blue precipitab and soluble in concentrated sulfuric acid ix; give EL greenish blue solution, said dye dyeing cotton, Wool, silk, and other fiberl s, bluish shades which can be developed to givo fast blue-black to greslr black .jhades.

2. The herein described new dyes obtainable by diazotizing the new disazo'dyo of claim 1 and developing with 'a developing again.

Mfierials dyed with the new di a-zo dye of claim 1.

Materials dyad with th s new diszmo d of claim 1, said dye being doveioped on the fibor of the nmtmial.

In fisstimony "whereof 1 of 

